The file DarkChocolate contains the cost per ounce ($) for a sample of 14 dark chocolate bars:

a. Construct a 95% confidence interval estimate for the population cost per ounce ($) of dark chocolate bars.
b. What assumption do you need to make about the population distribution to construct the interval in (a)?
c. Given the data presented, do you think the assumption needed in (a) is valid? Explain.

0.68 0.72 0.92 .14 1.42 0.94 0.77 0.57 15 0.57 0.55 0.86 .41 0.90